The industrial/promotional film "Rails to Rubber" (ca. 1940) was produced by the Twin Coach Company (builder of some of Seattle’s trackless trolley buses) and the Westinghouse Electric Manufacturing Company (supplier of the propulsion systems for those trackless trolley buses). The film documents the transition in Seattle from streetcars to trackless electric trolley buses. The film features rare and delightful color footage of the city (along with music and narration), including shots of a racially diverse downtown (on the brink of U.S. entry into World War II) and interesting sojourns with priceless tableaux of Seattle neighborhoods including Ballard, Fremont and West Seattle. It's a fascinating portrait of Seattle on the eve of an era of major changes brought about during the city's bustling home front years.